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sporadic E "alarm"

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  • sporadic E "alarm"

    When I'm home a good Es opening is never missed due to this one piece of gear.

    A receiver that covers the 55-88MHz range. Usually the unit is in scan mode going through TV2-6 video and audio frequencies but tropo scatter and meteor burst will frequently set it off. The best "alarm mode" here is tuning it to 67.250 which is the WTVY TV4 video carrier frequency at 62 miles away. At this distance the signal is solid enough to be a steady dead carrier with no noise. Any worthwhile sporadic E will overtake this with various sounds of buzzing, grinding, and screeching to echo through the house. Channel 5 would be a better video frequency to use but WKRG Mobile, AL is a bit strong here and by the time it is buzzing with Es noise, FM is usually already open.
    Of course this wont work where there is no TV transmitters to come in, but that almost never happens except for openings exclusively to Jamaica.
    and it wont be very effective next year in the US after analog shutdown.
    I have other 55-88MHz frequencies in mind and am working on putting together a bank of channels for that.
    Here's a video demo of the "Es alarm" in scan mode and other indicators:

    http://www.youtube.com/watch?v=hI5aFl5oiWc
    Last edited by KW4RZ; 07-06-2008, 07:43 PM. Reason: new video
    Randy KW4RZ Goldfield, Nevada DM17

  • #2
    My question: What are you going to use NEXT summer??

    Comment


    • #3
      I have a Uniden uBC9000XLT. I think you can tune to the bottom of the DTV signal as there is a carrier there. I'm going to experiment with this next week while I'm off work. Mind you, if all the carriers are set to an atomic standard there won't be any heterodyne.

      Comment


      • #4
        I don't like to leave the volume up on a vacant FM channel and listen to scratch and hiss waiting for Es to appear while I'm in the house. Next summer, I will rely on the pilot carriers for DTV2-6, and the mess of unidentifiable 72-76 MHz digital data signals to indicate good Es on the scanner. Unfortunately this is all inferior to analog 100kw TV2-6 signals and FM will likely already be open when much of DTV and 72-76MHz starts to show. FM Es will probably even come without any alert from the scanner depending on where to and how intense.
        Of course all the Mexican and other foreign TV2-6 will still be on the air and buzzing the scanner next summer. I'm not crying over the analog shutdown, in fact it will bring new possibilities for more interesting foreign TV DXing. Also many Es openings with the scanner and TV going nuts often show little or no significant FM band Es which to me is more of a waste of time to stay close by the radios waiting for stronger skip. So it's all good. I think it will still be effective, We'll see!
        Randy KW4RZ Goldfield, Nevada DM17

        Comment


        • #5
          I would use many of the same frequencies as before.

          After transition, lowband NTSC carrier frequencies will still be important, as they will still warn of Es to Canada, Mexico, Cuba and more exotic countries further south, as well as low power and class A stations in the US that may still broadcast in analog.

          FM receivers will receive TV audio with much more sensivity than television sets usually can, and can receive TV audio from a weak station even if there is interference from a strong (but not overwhelming) signal from a lowband ATSC transmitter.

          Video carrier frequencies:
          55.24 2-
          55.25 2z
          55.26 2+
          61.24 3-
          61.25 3z
          61.26 3+
          67.24 4-
          67.25 4z
          67.26 4+
          77.24 5-
          77.25 5z
          77.26 5+
          83.24 6-
          83.25 6z
          83.26 6+

          audio frequencies:

          59.74 2-
          59.95 2z
          59.76 2+
          65.74 3-
          65.75 3z
          65.76 3+
          71.74 4-
          71.75 4z
          71.76 4+
          81.74 5-
          81.75 5z
          81.76 5+
          87.74 6-
          87.75 6z
          87.76 6+

          Digital carrier frequencies can also trip a scanner, but not as easily as an analog can (the carrier is reduced, on a transmitter that is also lower in power to start with).

          54.310 2
          60.310 3
          66.310 4
          76.310 5
          82.310 6

          Six meters is covered by some scanners, and is a good indicator of Es activity:

          50.070 (center of subband used by CW beacons, which transmit whether hams know Es is in or they don't).

          50.130 (bottom of subband used by hams for SSB phone, and the first part of the band to be used when Es is in, if hams are aware so [may not alert one to off-hour or off-season openings)
          (scanners cannot offer intelligible reception of CW beacons or SSB phone, but these transmissions WILL TRIP THE SQUELCH of any scanner, resulting in noises).

          52.525
          Six meter FM phone calling channel (problem: very little activity in 6m FM nowadays, a good opening can go unnoticed - advantage: you can hear and understand 6m FM on a scanner, and get some idea where the opening is working)

          If your scanner has HF capability:

          10 meter FM simplex and output channels, can be understood on FM scanner:

          29.60
          29.62
          29.64
          29.66
          29.68

          CB channels often used (not in compliance with 47CFR95) by very high power AM transmitters (not understood on FM scanner, but will trip squelch)

          27.025
          27.085


          Rob Grant, Michigan
          Last edited by Robert Grant; 09-14-2008, 03:26 PM. Reason: added HF Es freqs, made corrections of typos in several freqs
          Comparing Sporadic-E skip to skip on the AM and shortwave bands is like comparing apples and oranges.

          Comparing tropo to skip is like comparing apples and bacon cheeseburgers.

          Comment


          • #6
            Originally posted by Robert Grant View Post
            Digital carrier frequencies can also trip a scanner, but not as easily as an analog can (the carrier is reduced, on a transmitter that is also lower in power to start with).

            54.310 2
            60.310 3
            66.310 4
            76.310 5
            82.310 6

            ...


            Rob Grant, Michigan
            Today, I've got Chicago's CH 5 (90 miles away) analogue audio (81.750) at S9, analogue video carrier (77.250) S8, and digital carrier (76.310) barely above the noise and buried in digital crap. (Icom R7100 + FM antenna stack)

            This will not be useful in detecting E's.

            Comment


            • #7
              It sure helps tell you if a DTV station is trying to take the channel. I use my R75 and set a preset for 55.309 USB so I can hear a tone. A tone will appear at an S1 or S2. I've seen it go over 10db over S9. The problem always has been the super-strong analogs, but with them gone we should get more than glimpses of DTV Es. I think I'll make use of this freq more than ever this summer.
              Mike B.
              Enfield, CT
              -72° 30' W/41° 59' N
              FN31RX

              Online since 1999 and still going at
              mikesdx.com

              Comment


              • #8
                Unless an opening is strong, it may not even be noticed! If that Chicago analog sig was S5, I wouldn't have even been able to detect the digital signal and also, even though the analog audio was S9, my digital TV wouldn't pick up the video, same antenna, same heading.

                Not good.

                Comment


                • #9
                  Originally posted by John Wilke K9RZZ View Post
                  Unless an opening is strong, it may not even be noticed!
                  Hi

                  I use the European section of this 6 meter ham map all the time

                  http://www.vhfdx.net/spots/map.php?L...c=&freq=&prop=

                  very useful to tell when an opening is happening !

                  Generally if 50 MHz band is open then channel E2,E3 will be "humming"
                  with me!


                  Hugh

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